PHOENIX (KSAZ) - Phoenix Police are working around the clock to catch a serial shooter. Seven people have been killed since March, including a 12-year-old girl.

The lead investigator in the case spoke exclusively to FOX 10.

The shootings began in March, continuing through June, when that 12-year-old girl was shot along with her mother and a family friend. The young girl's death weighs heavily on investigators.

"Nobody should have to face anything like this, let alone a child, so when something like that happens, it hits home for everybody," said Lt. Ed De Castro of the Phoenix Police.

Twelve-year-old Maleah Ellis was shot to death inside a car near 63rd Avenue and McDowell. The shooting happened on June 12th and it's believed the serial shooter has not struck since -- but that doesn't mean it's time to let down your guard.

"Don't stay out at night by yourself.. don't be outside alone, notice what's around you.. in these times, it is a really good thing to do," said De Castro.

Police have released two sketches in the case.

The lead detective in the case tells FOX 10 he believes the suspect is changing cars between shootings.

"He's gone from silver to white to a dark sedan, so at this point, I want everyone to be cognizant of any vehicle that is unfamiliar and acting suspicious in your neighborhood," he said.

Detectives have been working around the clock, reviewing cases and going over tips from Silent Witness, exhausting every lead and leaving no rock unturned.

"I'm 100 percent sure we'll catch this guy," said De Castro. "Somewhere, somebody out there has information. We will get that information."

The shooter hasn't struck in a while, but they also took a month-long break in the early part of this crime spree.